Advent of Code 2019 - Day 9Sensor Boost

| Problem statement | Source code | Tags: Intcode

• To add support for relative mode, the relative_base is added to the Program class. Because eval_param and write_to now relies on two states: the memory and the relative base, I just make them member functions so they can directly access on this. Some other things are also incorporated into the class.
• All memory values are now long long instead of int.
• The memory is now a map<long long, long long> instead of a vector<long long>, so that the memory can be indexed at arbitrary addresses without greatly growing its physical size.